Collection Efficiency of Deposition by Filtrating Bulk Sampler Compared with Wet/Dry Sampler

Abstract

Wet deposition and a part of dry depositions were collected by filtrating bulk sampler and wet/dry sampler in Kobe from June 1986 to May 1990, and at 7 stations over Japan from A pril 1984 to March 1988, and concentrations of dissolved ions and insoluble components in the deposition were determined. These measurements showed that the pH value by filtrating bulk sampler was higher by O.1-0.2 than by wet/dry ampler and that the deposition by the former was 20--40% smaller than by the latter.
The results of experiments to make clear the cau se of the low collection efficiency are as f ollows. Dry deposition by filtrating bulk sampler was 30% lower than that by wet/dry sampler, while filtrating bulk sampler showed high collection efficiency of 90% for wet depoilsition. Sampling error of filtranting bulk sampler was caused by adsorption of chemical species to sampler to sampler surface, as well as by the low collection efficiency of dry deposition.
Filtrating bulk sampler was thought to be the most suitable handy sampler for merly, but, these results indicate that the use of this sampler should be limited only for simple measurement such as, simultaneous measurement at many sites simply for an analysis of spatial d istribution of deposition, preliminary measurement for long -term monitoring by wet/dry sampler and so on.